1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
|
/**
* @file libavformat/yop.c
* Psygnosis YOP demuxer
*
* Copyright (C) 2010 Mohamed Naufal Basheer <naufal11@gmail.com>
* derived from the code by
* Copyright (C) 2009 Thomas P. Higdon <thomas.p.higdon@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/intreadwrite.h"
#include "avformat.h"
typedef struct yop_dec_context {
AVPacket video_packet;
int odd_frame;
int frame_size;
int audio_block_length;
int palette_size;
} YopDecContext;
static int yop_probe(AVProbeData *probe_packet)
{
if (AV_RB16(probe_packet->buf) == AV_RB16("YO") &&
probe_packet->buf[6] &&
probe_packet->buf[7] &&
!(probe_packet->buf[8] & 1) &&
!(probe_packet->buf[10] & 1))
return AVPROBE_SCORE_MAX * 3 / 4;
return 0;
}
static int yop_read_header(AVFormatContext *s, AVFormatParameters *ap)
{
YopDecContext *yop = s->priv_data;
ByteIOContext *pb = s->pb;
AVCodecContext *audio_dec, *video_dec;
AVStream *audio_stream, *video_stream;
int frame_rate, ret;
audio_stream = av_new_stream(s, 0);
video_stream = av_new_stream(s, 1);
// Extra data that will be passed to the decoder
video_stream->codec->extradata_size = 8;
video_stream->codec->extradata = av_mallocz(video_stream->codec->extradata_size +
FF_INPUT_BUFFER_PADDING_SIZE);
if (!video_stream->codec->extradata)
return AVERROR(ENOMEM);
// Audio
audio_dec = audio_stream->codec;
audio_dec->codec_type = AVMEDIA_TYPE_AUDIO;
audio_dec->codec_id = CODEC_ID_ADPCM_IMA_WS;
audio_dec->channels = 1;
audio_dec->sample_rate = 22050;
// Video
video_dec = video_stream->codec;
video_dec->codec_type = AVMEDIA_TYPE_VIDEO;
video_dec->codec_id = CODEC_ID_YOP;
url_fskip(pb, 6);
frame_rate = get_byte(pb);
yop->frame_size = get_byte(pb) * 2048;
video_dec->width = get_le16(pb);
video_dec->height = get_le16(pb);
video_stream->sample_aspect_ratio = (AVRational){1, 2};
ret = get_buffer(pb, video_dec->extradata, 8);
if (ret < 8)
return ret < 0 ? ret : AVERROR_EOF;
yop->palette_size = video_dec->extradata[0] * 3 + 4;
yop->audio_block_length = AV_RL16(video_dec->extradata + 6);
// 1840 samples per frame, 1 nibble per sample; hence 1840/2 = 920
if (yop->audio_block_length < 920 ||
yop->audio_block_length + yop->palette_size >= yop->frame_size) {
av_log(s, AV_LOG_ERROR, "YOP has invalid header\n");
return AVERROR_INVALIDDATA;
}
url_fseek(pb, 2048, SEEK_SET);
av_set_pts_info(video_stream, 32, 1, frame_rate);
return 0;
}
static int yop_read_packet(AVFormatContext *s, AVPacket *pkt)
{
YopDecContext *yop = s->priv_data;
ByteIOContext *pb = s->pb;
int ret;
int actual_video_data_size = yop->frame_size -
yop->audio_block_length - yop->palette_size;
yop->video_packet.stream_index = 1;
if (yop->video_packet.data) {
*pkt = yop->video_packet;
yop->video_packet.data = NULL;
yop->video_packet.size = 0;
pkt->data[0] = yop->odd_frame;
pkt->flags |= AV_PKT_FLAG_KEY;
yop->odd_frame ^= 1;
return pkt->size;
}
ret = av_new_packet(&yop->video_packet,
yop->frame_size - yop->audio_block_length);
if (ret < 0)
return ret;
yop->video_packet.pos = url_ftell(pb);
ret = get_buffer(pb, yop->video_packet.data, yop->palette_size);
if (ret < 0) {
goto err_out;
}else if (ret < yop->palette_size) {
ret = AVERROR_EOF;
goto err_out;
}
ret = av_get_packet(pb, pkt, 920);
if (ret < 0)
goto err_out;
// Set position to the start of the frame
pkt->pos = yop->video_packet.pos;
url_fskip(pb, yop->audio_block_length - ret);
ret = get_buffer(pb, yop->video_packet.data + yop->palette_size,
actual_video_data_size);
if (ret < 0)
goto err_out;
else if (ret < actual_video_data_size)
av_shrink_packet(&yop->video_packet, yop->palette_size + ret);
// Arbitrarily return the audio data first
return yop->audio_block_length;
err_out:
av_free_packet(&yop->video_packet);
return ret;
}
static int yop_read_close(AVFormatContext *s)
{
YopDecContext *yop = s->priv_data;
av_free_packet(&yop->video_packet);
return 0;
}
static int yop_read_seek(AVFormatContext *s, int stream_index,
int64_t timestamp, int flags)
{
YopDecContext *yop = s->priv_data;
int64_t frame_pos, pos_min, pos_max;
int frame_count;
av_free_packet(&yop->video_packet);
if (!stream_index)
return -1;
pos_min = s->data_offset;
pos_max = url_fsize(s->pb) - yop->frame_size;
frame_count = (pos_max - pos_min) / yop->frame_size;
timestamp = FFMAX(0, FFMIN(frame_count, timestamp));
frame_pos = timestamp * yop->frame_size + pos_min;
yop->odd_frame = timestamp & 1;
url_fseek(s->pb, frame_pos, SEEK_SET);
return 0;
}
AVInputFormat yop_demuxer = {
"yop",
NULL_IF_CONFIG_SMALL("Psygnosis YOP Format"),
sizeof(YopDecContext),
yop_probe,
yop_read_header,
yop_read_packet,
yop_read_close,
yop_read_seek,
.extensions = "yop",
.flags = AVFMT_GENERIC_INDEX,
};
|
